This invention relates to electrical connectors and especially to connectors for forming solder connections between elongate electrical conductors.
Electrical connectors which contain solder inserts are widely used for forming solder connections between elongate electrical conductors. Such connectors are described in U.S. Pat. Nos. 3,243,211, 4,282,396 and 4,283,596 and International Patent Application Publication No. WO91/11831, the disclosures of which are incorporated herein by reference. Such electrical connectors are satisfactory for most applications, but in some situations they suffer from the drawback that it is normally possible for the elongate conductors (e.g. wires) to slip out of the connector prior to the formation of the solder connection.
In the manufacture of automotive harnesses, for example, it is usual to assemble the harness and form temporary connections between the wires and cables so that an electrical current or signal may be passed through the assembly in order to verify that the harness has been assembled correctly. It is only after such verification is obtained that permanent electrical connections are formed. The electrical connectors mentioned above are often unsatisfactory for such an application, because they generally cannot be used to form temporary joints which are dependable so that the harness can be tested prior to formation of the permanent solder joint.
The electrical connectors described in International Patent Application No. WO92/00616 overcome the above drawbacks. These devices contain a metallic connecting element, made from copper for example, having a tapering internal surface which has a screw thread, so that a temporary electrical connection between a bundle of wires can be formed by screwing them into the connecting element. They also contain a solder insert for forming a permanent connection between the wires, so that, for example, once an automotive harness has been tested using temporary connections, these connections can be made permanent simply by heating the connectors so as to melt the solder and form solder connections. Whilst these connectors perform excellently they have the drawback that because the solder joint is formed inside the connecting element it is difficult to inspect. In addition, in comparison to a connection formed entirely by solder, the presence of the connecting element normally raises the weight of the connection and also its size, for example due to the protrusion of a circumferentially extending ridge in the area of the connection.